XRAY XB8 2016 69mm "3-Dot" Front Shock Spring Set. The XB8 2016 springs have a mix of progressive & linear characteristics. The springs are slightly progressive, but under larger compression they change characteristics to become more linear. This gives an excellent feeling & feedback of the car in all different track conditions. These XRAY shock springs, like all other XRAY springs, are manually measured, selected and matched into pairs to guarantee precisely equal length and damping characteristics.